Red Bull boss Christian Horner said today it was “staggering” that Ross Brawn had not yet signed new world champion Jenson Button to an extended contract.

As Button finish third in the faster second practice session for the inaugural Abu Dhabi Grand Prix, Horner claimed that Button's demands for a substantial pay rise were not excessive and he warned Brawn other teams, thought to include McLaren and Toyota, were ready to snap up Button.

Horner, who has already re-signed Sebastian Vettel and Mark Webber for 2010, said: “I find it staggering that Jenson, having won the world championship and had a brilliant year, hasn't concluded a deal with his team yet.

“If I was Brawn GP I would get off the fence pretty quickly because he's a very attractive proposition and there are some good seats that are open. I'm sure that's not gone unnoticed by Ross, but I wouldn't hang about if I were him.”

Button has revealed that talks about a new deal were taking place in Abu Dhabi this weekend. But it would seem there is a reluctance by Brawn to increase their champion's current retainer of £3million to the £8m he is reported to be asking for. Horner, however, insisted that Button's pay claim was not excessive, adding:
“Jenson is the reigning world champion, he's done a brilliant job this year, and I don't think he's being greedy.

“There are probably five drivers in the pit lane who are earning more than his reported demands.”
Button's current team-mate, Rubens Barrichello, is almost certainly about to start his last race for Brawn GP.

The veteran Brazilian, eighth fastest this afternoon, is expected to be named on Monday as Williams' new team leader, with Germany's Nico Rosberg moving the other way to Brawn.

Barrichello would not confirm the tie-in with Williams, who have announced they are to switch from Toyota to Cosworth engines next season, but he admitted: “Williams has always been a team that anyone would look at. It is one of the best teams out there, and it is on the way up.”

So far as the season's finale is concerned, Barrichello warned that a basic flaw in the design of the 3.451-mile Yas Marina circuit could lead to Sunday's Grand Prix being stopped.

At the end of the pit lane, the cars have a sharp left turn into a narrow tunnel which takes them underneath the track and back out the other side where they funnel back into the race.

Barrichello's fear is that if a car fails to negotiate the tunnel, it will block the exit for everybody else. He said: “You don't have any run-off and if somebody crashes there it is definitely going to be a red flag.

“They've tried to make the circuit look amazing, and it does look fantastic, but I don't think the pit exit worked.”

Heikki Kovalainen led a McLaren one-two in practice today, the Finn's time of 1min 41.307sec being just 0.197sec ahead of team-mate Hamilton. Kimi Raikkonen, in his last race for Ferrari, was 10th, just 0.624sec behind his pace-setting compatriot.